Table of Contents
Summary of Contents for Pyramid D100
- Page 1 D100 Digital Pulse Processor User Manual Pyramid Technical Consultants, Inc. 1050 Waltham Street Suite 200, Lexington MA 02421 USA US: TEL: (781) 402 1700 ♦ FAX: (781) 402-1750 ♦ EMAIL: SUPPORT@PTCUSA.COM Europe: TEL: +44 1273 493590...
-
Page 2: Table Of Contents
Basic setup .................................16 Signal cables ..............................17 Signal cables ..............................17 Getting Started with the PSI Diagnostic host software..................19 Installing the PSI Diagnostic Program ........................19 Running the PSI Diagnostic Program ........................19 Running the PSI Diagnostic program........................21 D100 User Manual D100_UM_081027 Page 2 of 46... - Page 3 PSI System Controls and Diagnostics Acquiring spectra with the PSI Diagnostic program....................23 Principle of Operation...............................26 Wideband digital pulse processing .........................26 D100 Circuit Overview............................27 Optimizing the Pulse Processing Algorithm ......................30 Overview of the FPGA algorithm ...........................30 Regions of interest .............................30 Data processing stages ............................31 Pulse processing user parameters ..........................32...
- Page 4 PSI System Controls and Diagnostics Front panel indicators ............................39 LED block................................39 Rear panel indicators .............................39 Fault-finding ................................40 Maintenance................................42 Returns procedure..............................43 Support ..................................44 Declaration of Conformity............................45 Revision History.................................46 D100 User Manual D100_UM_081027 Page 4 of 46...
-
Page 5: Safety Information
The unit is designed to make measurements in Measurement Category I as defined in the standard. CAUTION. The D100 does not generate high voltages, but is designed to control a high voltage supply for a photomultiplier, which may typically be rated from 1000 to 2000 V DC. The user must therefore exercise appropriate caution when using the device and when connecting cables. - Page 6 Direct current Earth (ground) terminal Protective conductor terminal Frame or chassis terminal Equipotentiality Supply ON Supply OFF CAUTION – RISK OF ELECTRIC SHOCK CAUTION – RISK OF DANGER – REFER TO MANUAL D100 User Manual D100_UM_081027 Page 6 of 46...
-
Page 7: Models
PSI System Controls and Diagnostics 3 Models D100 Digital pulse processor unit. -CxRy Input amplifier feedback option capacitance x pF, resistance y kohm. Example: D100-C100R1.0 D100 with 100 pF and 1.0 kohm parallel feedback. D100 User Manual D100_UM_081027 Page 7 of 46... -
Page 8: Scope Of Supply
PSI System Controls and Diagnostics 4 Scope of Supply D100 model as specified in your order. USB memory stick containing: User manual PSI Diagnostic software guide Software installation guide PSI diagnostic software files USB drivers and utilities Optional items as specified in your order. -
Page 9: Optional Items
A200 USB to fiber-optic loop adaptor. A300 Ethernet to fiber-optic loop adaptor. A500 intelligent multi-loop cell controller with Ethernet interface and direct input channels for up to ten parallel D100 data streams. D100 User Manual D100_UM_081027 Page 9 of 46... -
Page 10: Intended Use And Key Features
6 Intended Use and Key Features 6.1 Intended Use The D100 is intended for the counting and spectrometry of single event current pulses generated by sodium iodide scintillator/photomultiplier detectors operated in pulse-counting mode. The D100 has design features which make it tolerant of electrically noisy environments, but the place of use is otherwise assumed to be clean and sheltered, for example a laboratory or light industrial environment. -
Page 11: Key Features
Fast fiber-optic serial interfaces built-in. Selectable baud rates. Can be operated in a fiber-optic serial communication loop with up to fourteen other devices. 100BaseT Ethernet available through the A300 and A500 interfaces. D100 User Manual D100_UM_081027 Page 11 of 46... -
Page 12: Specification
< 0.1g all axes (1 to 1000Hz) Shipping and storage -10 to 50C environment < 80% humidity, non-condensing vibration < 2 g all axes, 1 to 1000 Hz Dimensions (see figures 1 and 2). D100 User Manual D100_UM_081027 Page 12 of 46... - Page 13 Status LEDs Power Xmit Address Direct +24VDC Power In Address 2.1mm Jack Selector Fiber-optic Direct Fiber-optic RX ST Bayonet ST Bayonet Fiber-optic TX ST Bayonet Figure 1. D100 chassis end panels. Dimensions mm. D100 User Manual D100_UM_081027 Page 13 of 46...
- Page 14 PSI System Controls and Diagnostics 3.66 Mounting Hole 77.5 62.0 80.2 140.0 28.2 0.74 147.1 158.1 Figure 2. D100 case side and plan views. Dimensions mm. D100 User Manual D100_UM_081027 Page 14 of 46...
-
Page 15: Installation
The D100 must not be mounted in a place with high flux of ionizing radiation, as this could lead to soft errors and possible incorrect processing of signals. To keep the potential error rate below one event per day, we recommend a maximum background dose rate of 1 mSv / hr. -
Page 16: Connection To Signal Source
Pyramid Technical Consultants, Inc. before attempting to use the D100. If you are using a photomuliplier, the base must not include a pre-amplifier, because the D100 is designed to receive the anode current pulses directly. The high voltage supply may be external or integrated with the base. -
Page 17: Signal Cables
The D100 should be located as close to the source of the signal as possible. If space permits, it can be connected directly to the photomultiplier base with a suitable through connector. Long signal cables increase the chances of seeing unwanted signals and noise. - Page 18 Base A500 D100 HV PSU Photomultiplier Base A500 D100 HV PSU Photomultiplier Base A500 D100 HV PSU Photomultiplier Base A500 D100 Figure 4. Example multi-channel system using the A500 real-time cell controller D100 User Manual D100_UM_081027 Page 18 of 46...
-
Page 19: Getting Started With The Psi Diagnostic Host Software
9 Getting Started with the PSI Diagnostic host software Before installing the D100 in its final location, and if it is the first time you have used a D100, we recommend that you familiarize yourself with its operation on the bench. You can check the unit powers up correctly, establish communications, and operate peripheral devices such as HV supplies. - Page 20 9.3 Running the PSI Diagnostic program Clicking on the D100 entry in the System window search tree brings up the D100 screen with the data tab showing. This is where energy spectra will display, where you can see readbacks for temperatures, and set the DAC output that programs a high voltage supply for a multiplier.
-
Page 21: Running The Psi Diagnostic Program
PSI System Controls and Diagnostics Figure 6. D100 window selected from the discovered devices Clicking on the setup tab will display the controls for the FPGA digital pulse analysis, described in section 11, plus other parameters which control how the PSI Diagnostic handles and displays the data. - Page 22 The Bias Scale parameter should be set so that the high voltage supply output scales correctly for the 0 to 2.048 output from the D100. The value is the output voltage per volt of demand. Check that the program voltage to the HV supply appears at the appropriate pins (see section 12.1) when the bias voltage is set.
-
Page 23: Acquiring Spectra With The Psi Diagnostic Program
PSI System Controls and Diagnostics Figure 8. D100 window device tab showing communication status, version numbers and code upload utility. 9.4 Acquiring spectra with the PSI Diagnostic program If you have the parts available to hand, you can connect up a scintillator and photomultiplier on the bench as shown in figure 3. - Page 24 The cursor now reads out in energy. You can define multiple regions of interest, and the software will display the total counts accumulated into each of them. D100 User Manual D100_UM_081027 Page 24 of 46...
- Page 25 PSI System Controls and Diagnostics Figure 10. Na spectrum after energy calibration. Multiple regions of interest selected. D100 User Manual D100_UM_081027 Page 25 of 46...
-
Page 26: Principle Of Operation
The D100 uses a different approach. The basic pulse shape from the multiplier anode is preserved and digitized at high rate. All pulse size and shape analysis then occurs in a FPGA (field-programmable gate array) device using numerical processing algorithms. -
Page 27: D100 Circuit Overview
Microcontroller Temperature sense Figure 12. D100 block schematic. The amplifier stage is a fast current to voltage converter with 499 ohm feedback. The circuit allows optional series input resistance at x and different feedback at y in order to adapt to different input signal characteristics. - Page 28 -100 Time/nSecs 100nSecs/div Figure 13. Circuit simulation, current and voltage waveforms in the D100 input stages, 30 pF input load. The red curve is a simulated sodium iodide detector output current pulse, which typically includes a very fast rise followed by an exponentially falling tail with decay constant around 250 nsec.
- Page 29 PSI System Controls and Diagnostics -100 -100 Time/nSecs 100nSecs/div Figure 14. Circuit simulation, current and voltage waveforms in the D100 input stages, 180 pF input load. D100 User Manual D100_UM_081027 Page 29 of 46...
-
Page 30: Optimizing The Pulse Processing Algorithm
The task of the D100 is thus to integrate the current pulses, making corrections as necessary for background offsets and overlapping pulses. The algorithm running in the D100 FPGA is designed to extract the best energy resolution even when there is the potential for degradation due to pulse overlap at high input rates. -
Page 31: Data Processing Stages
However it is counted, as a rejected pulse. The D100 counts the number of pulses accepted and pulses which were rejected for not meeting the width requirements or for violating the shaping time or pile up time constraints. Pulses which are too small to exceed the pulse or derivative discriminator are not counted, however, as they are generally due to noise. -
Page 32: Pulse Processing User Parameters
11.2.2 Peak Width The D100 measures the width of the pulses at half maximum. If the width falls outside of the range provided by the Min and Max parameters, it is discarded. The range is inclusive; if the width is exactly equal to Min or Max, it is counted as valid. -
Page 33: Pile Up
Shaping Time = 2 µsec, and if the first pulse is at t = 0, the second at t = 2.5 µsec, and a third arrives at at t = 5 µsec, then only the first pulse is energy analyzed and assigned to a region of interest. All three pulses are counted, however. In other words, the D100 implements a paralyzable deadtime model. -
Page 34: Decaytime
Figure 18. Overlapping pulses showing assumed continuation of the first pulse under the second. Figure 19. Effect of overlapping prior pulse on integrated area of second pulse removed by subtracting the assumed decay tail. D100 User Manual D100_UM_081027 Page 34 of 46... -
Page 35: Gain, Offset
PSI System Controls and Diagnostics 11.2.8 Gain, Offset The D100 has a standard default 1024 bin diagnostic histogram that is available before any regions of interest are sent by the host. Binning into this diagnostic histogram is according to the... -
Page 36: Connectors
The test pulser LED is returned to digital ground on pin 2 via 2 kohm and a switching transistor controlled by the FPGA. For a typical LED the forward current in the on state will be 1.5 mA. D100 User Manual D100_UM_081027... -
Page 37: Pulse Signal Input
12.2.2 Fiber-optic direct data stream output Fiber-optic transmitter, ST bayonet. Light gray shell. 12.2.3 Fiber-optic loop communications Transmitter / receiver pair, ST bayonet. Transmitter light grey shell, receiver dark grey shell. Xmit D100 User Manual D100_UM_081027 Page 37 of 46... -
Page 38: Controls And Indicators
16 position rotary switch setting device address. Choice of address is arbitrary, but each device in a fiber-optic loop system must have a unique address. Setting Function (Reserved to loop controller) 1-15 Available address settings. Indicated on switch as hexadecimal values 1-F. D100 User Manual D100_UM_081027 Page 38 of 46... -
Page 39: Front Panel Indicators
Activity: Lit to indicate device is initiated and is processing pulses Network: Lit to indicate messages are being transacted on the fiber-optic communication loop Device: Blinks to indicate processor is booted and working normally. 13.4 Rear panel indicators None D100 User Manual D100_UM_081027 Page 39 of 46... -
Page 40: Fault-Finding
Resolution improves if gain is Increase gain. increased. Cable from photomuliplier to Resolution improves with Reduce the cable length if D100 too long. shorter cable. possible, otherwise increase the Shaping time. Unstable energy calibration Unstable high voltage Check HV stability with Replace supply. - Page 41 High proportion of rejected Pile up time too long. Reduce pile up time, pulses. consistent with sufficient energy resolution. Photomultiplier gain Loss reduced if gain Run at higher multiplier gain. suppression by high rate. increased. D100 User Manual D100_UM_081027 Page 41 of 46...
-
Page 42: Maintenance
The D100 does not require routine maintenance. There are no user-serviceable parts inside. The D100 is fitted with a 1.1 A automatically resetting positive temperature coefficient (PTC) fuse in the 24 VDC input. No user intervention is required if the fuse operates due to overcurrent. -
Page 43: Returns Procedure
16 Returns procedure Damaged or faulty units cannot be returned unless a Returns Material Authorization (RMA) number has been issued by Pyramid Technical Consultants, Inc. If you need to return a unit, contact Pyramid Technical Consultants at support@ptcusa.com, stating - model... -
Page 44: Support
PSI System Controls and Diagnostics 17 Support Manual and software driver updates are available for download from the Pyramid Technical Consultants website at . Technical support is available by email from www.ptcusa.com support@ptcusa.com. Please provide the model number and serial number of your unit, plus relevant details of your application. -
Page 45: Declaration Of Conformity
PSI System Controls and Diagnostics 18 Declaration of Conformity D100 User Manual D100_UM_081027 Page 45 of 46... -
Page 46: Revision History
PSI System Controls and Diagnostics 19 Revision History The release date of a Pyramid Technical Consultants, Inc. user manual can be determined from the document file name, where it is encoded yymmdd. For example, M10_UM_080105 would be a M10 manual released on 5 January 2008.